Dual wildfires in California threaten 1,300 homes

Two forest fires in California continue to expand as officials warn the blazes could threaten more than a thousand homes.

One forest fire burning near Big Sur, on California's scenic central coast, has nearly doubled in size to almost 777 hectares since erupting Friday in almost inaccessible terrain about eight kilometres south of Garrapata State Park.

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The state forestry department says the blaze is a threat to 1,000, homes and the Monterey County community of Palo Colorado has been ordered evacuated.

Another wildfire burning north of Los Angeles has grown to more than 2,200 hectares overnight, and there's zero containment.

The fire erupted Friday afternoon in the Sand Canyon area near State Route 14 as the region was gripped by triple-digit heat and very low humidity levels. Some 300 homes have been ordered evacuated.

The blaze is being battled by 300 firefighters as well as a fleet of helicopters and airplanes.

Much of the sky over Greater Los Angeles was filled with heavy smoke Saturday morning, and ash had fallen in some areas.

Authorities have issued an advisory warning that air quality may reach unhealthy levels in central Los Angeles and adjacent valleys.